Directional-beam antenna

ABSTRACT

A directional beam antenna employs a pair of elongate, parallel, U-shaped members having a dipole connected at one end and a reflector connected at the other end. The U-shaped members are spaced apart and have their edges (legs of a U) extending toward one another. The reflector may be constructed of at least two spaced apart and connected parallel elongate U-shaped members. The dipole includes a pair of dipole halves which abut and are connected to the first-mentioned U-shaped members at portions defining the bases of the respective U&#39;&#39;s. A coaxial cable extends directly through a channel defined by the base and legs of one of the U-shaped members which support the dipole and a connection member bridges the supporting U-shaped members for mechanical and electrical connection of the coaxial cable to the dipole halves.

United States Patent Scheuerecker et al.

[54] DIRECTIONAL-BEAM ANTENNA [151 3,686,673 [451 Aug. 22, 1972 3,550,144 12/1970 Barbano et al. ..343/792.5 [72] Inventors: Friedrich Scheuenecker, Baldham;

Johann Schlagbauer, Munich, both Pnmary f Llebermiimn f Germany Att0rneyH1ll, Sherman, Meronl, Gross & Simpson [73] Assignee: gglrige & Schwarz, Muenchen, Ger- [57] ABSTRACT A directional beam antenna employs a pair of elon- [22] 1970 gate, parallel, U-shaped members having a dipole con- [21] Appl. No.: 94,280 nected at one end and a reflector connected at the other end. The U-shaped members are spaced apart 3O and have their edges (legs of a U) extending toward 1 Foreign Application Pnomy Data one another. The reflector may be constructed of at 1969 Germany 69 43 104-5 least two spaced apart and connected parallel elongate U-shaped members. The dipole includes a pair of US. Clhalves abut and'are connected to the Cl. .-H0lq first mentioned U haped members at portions defin- [58] held of Search-"343N925, 815, 908, ing the bases of the respective Us. A coaxial cable ex- 343/818 873 tends directly through a channel defined by the base a and legs of one of the U-shaped members which sup- [56] Rem-mm cued port the dipole and a connection member bridges the UNITED STATES PATENTS supporting U-shaped members for mechanical and 2 297 329 9/l942 Scheldorf 343/815 electrical connection of the coaxial cable to the dipole 2,943,326 6/1960 Thayer ..343/90s yes 3,518,690 6/1970 Schick et a1. ..343/792.5 12 Claims, 4 Drawing Figures Li! H V I r" H J-/2 Patented Aug. 22, 1972 2 Sheets-Sheet l Patented Aug. 22, 1972 3,686,673

2 Sheets-Sheet 2 BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to a directional beam antenna having a reflector, elongate U-shaped members which are attached to the reflector with the members parallel to one another and spaced apart at a small distance, and a pair of dipole halves which are abutted to and attached to the planar base sections of the U-shaped members.

2. Description of the Prior Art French Letters Pat. No. 1,099,513 is concerned with an antenna which employs a reflector consisting of a metal sheet plate on which two U-shaped members are attached at about their centers and which lie parallel to one another, standing upright in a closely spacedrelationship. The U-shaped members are thereby arranged with their base sections facing each other and on the inside of one of the U-shaped members, which is opened to the outside of the antenna arrangement, a coaxial cable for feeding a dipole is extended through the reflector to the opened center of the dipole. The dipole halves are attached by screws through flange sections to the planar base sections of the U-shaped members. At the one U-shaped member along which the coaxial cable is extended, the end of the flange section of the dipole half is constructed in the shape of a fork and serves simultaneously as a mounting bracket for the coaxial cable. A directional beam antenna of this kind is relatively complicated in its construction and cannot be produced simply and inexpensively in mass production.

The prior art also recognizes directional beam antennas having angular reflectors (British Letters Pat. No. 875,281) wherein the reflector is constructed of parallel angular-shaped members and rods which are attached crosswise to such members. The supports for the two dipole halves are constructed in tubular configuration and are bluntly attached to a center flat iron portion of the reflector. This prior art reflector construction is also relatively complicated and cannot be simply produced as a pre-constructed component in mass production in a plant, since the antenna utilizes the reflector as part of the antenna mast itself. From an electrical point of view, this prior art directional beam antenna is also not properly dimensioned since the desired wave resistance curve for the feed system cannot be obtained without difficulty because of the round dipole supports.

Finally, German Letters Pat. No. 807,099 and Austrian Letters Pat. No. 266,924 concerning dipoles and their supports illustrate that the prior art recognizes the improvement of the wave resistance curve between two shaped members which lie opposite each other by arranging these shaped members with their shank portions turned toward each other to thus form a kind of hollow chamber between the members.

SUMMARY OF THE INVENTION It is a primary object of this invention to further develop and improve a directional beam antenna of the kind hereinbefore mentioned in a manner to obtain a particularly favorable design which allows a very simple and inexpensive production of a directional beam antenna as a pre-fabricated component simultaneously taken advantage of mass production techniques in a factory, and which, of course, also has optimum favorable electrical properties.

This objective is realized by means of the constructional features of the invention wherein a directional beam antenna can be assembled very simply and inexpensively from U-shaped members by means of welding. Such a directional beam antenna is far superior to the former common constructions with regard to mechanical stability. In addition, very favorable electrical properties can be obtained. A directional antenna according to this invention can be completely assembled in a factory and, at the place where the antenna is set up, the antenna can be attached in each desired position simple by means of attaching the reflector to the antenna mast. The desired cable guidance, and primarily the construction of the cable end connection in the center of the dipole, allows a very quick and simple positioning of the cables, and thus the connection of each antenna to the mast. Since no changes have to be made at the antenna construction sites during the mounting process, good mechanical and electrical properties remain which have been pre-selected in the factory.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention will be best understood from the following detailed description of an exemplary embodiment thereof taken in conjunction with the accompanying drawing in which:

FIG. 1 is a side elevational view of a high frequency directional beam antenna, for example for the frequency range of about 87-100 MHz;

FIG. 2 is a top view of the antenna illustrated at FIG. 1:

FIG. 3 is a sectional view taken generally along the line III-III of FIG. 1; and

FIG. 4 is an enlarged view of a portion of the apparatus of FIG. 1 shown partially in section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The directional beam antenna comprises a reflector 1 which, in the illustrated sample embodiment includes a pair of U-shaped members 2 which are arranged parallel to each other and spaced apart at some distance. The members 2 are welded together at the ends and in the center via flat iron members 3 and 4. In some cases it may be favorable to arrange a plurality of U-shaped members parallel each other and to connect them in a suitable manner by means of flat iron members or by other suitable means to form the reflector I. A pair of U-shaped members 5 and 6 are welded to the center flat iron member 4, vertical to the reflector I and at a given distance from each other, as illustrated in the sample embodiment. These U-shaped members are turned with their edges defined by the legs of a U extending toward each other. As an example, in the illustrated sample embodiment, a pair of U-shaped members 90=40=2 mm are applied and the distance of the U-shaped members from each other is relatively small, for example only about 40 mm.

A pair of dipole halves 7 and 8 are welded to the outside of these two metal U-shaped members 5 and 6 which extend from the reflector 1 parallel to each other. Each dipole half comprises a tube of about M4 length and of a diameter which corresponds to approximately the width of the shaped members 5 and 6, thus approximately a diameter of 90 mm in the sample embodiment illustrated. The tubes 7 and 8 are abutted and welded onto the outside of respective ones of the U- shaped members 5 and 6, and are closed at their distal ends by means of respective plasticcaps (not'shown). The distance between the M2 dipole formed by means of the 2 pair of tubes 7,8 and the reflector 1 is approximately M4 as is practiced in the art. The distance between the U-shaped members 5 and 6 depends on the desired wave resistance of a line of symmetry which is formed by these members. With direction of beam fields of this kind a relatively large wave resistance between the pair of U-shaped members 5 and 6 is desirable. For this reason, the U-shaped members 5 and 6 are arranged with their edges (legs of the cross-sections) turned toward each other, since this results in the lowest possible capacitance between the members,

which is practically determined only by means of the narrow edges which are opposed to each other. A small capacitance causes a large wave resistance. This enables an arrangement of the pair of shaped members in relatively close proximity, which is also desirable for mechanical reasons.

The free ends of the shaped members 5 and 6 are closed ofl at the frontal side by means of transverse plates 9 and 10 which are welded thereto. A connection member 11 made of insulating material is attached to the transverse plates 9 and 10 from the outside, which connection member 11 bridges the ends of the pair of shaped members, in illustrated in section in FIG. 4; it connects the two free ends of the shaped members mechanically with each other and accommodates the electrical connection members of the'pair of dipole halves 7 and 8. A coaxial feed cable 12 is extended from the back of the reflector 1 through an opening in the flat iron member 4 to the connection member 11, and along the bottom of one of the shaped members 6. The cable 12 is mounted at the inside of the shaped member 6 by way of a mounting sheet 19 and ends in a plug-like end connection 13 which is galvanically connected with the outer conductor of the coaxial cable. This end connection 13 is screwed into the transverse plate 9. The inner conductor 14 of the coaxial cable is soldered to a conductor bridge 15 or screwed to the conductor bridge via a nipple. This conductor bridge 15 is arranged coaxially of the inner end of the tubular connection part 11 which is made of insulating material. The other end of the conductor bridge 15 is connected with a bolt 16 which is screwed into the transverse plate 10. The electrical connection of the dipole halves 7 and 8 which are welded onto the shaped members 5 and 6 is effected via the transverse plates 9 and 10. The interior or the tubular connection member 11 is accessable from the frontal sides and can be closed off by means of screw locks or plugs 17.

A C-shaped member can also be utilized in case of the U-shaped member for the members 5 and 6 with edges which are directed toward the inside; however, which edges are selected as narrow as possible so that the capacitances between the edges remains as low as possible.

In some cases it is advantageous to coat or encase the entire connection point of the dipole halves by means of a member lb which protects against ice.

A dipole antenna according to this invention may be attached very simply to a suspension tower, for instance, via connecting flat iron members. The electrical connection can also be effected very simply and quickly due to the entirely straight extension of the coaxial cable to the connection point. After the end connection 13 is screwed in, it is merely necessary to solder or screw the inner end of the conductor 14 with a conductor bridge 15. Bends in the cable have therefore been avoided.

Many changes and modifications of the invention may become apparent to those skilled in the art departing from the spirit and scope of the invention, and it is to be understood that we intend to include within the patent warranted hereon all such changes and modifications as may reasonably and properly be included within the scope of our contribution to the art.

What we claim is:

1-. A directional beam antenna comprising:

a pair of parallel spaced-apart U-shaped members each having a pair of legs and a base interconnecting said legs, said legs of each said member extending toward the legs of the other said member;

a pair of dipole halves each welded to and extending from respective ones of said bases at one end of said U-shaped members;

a connecting member welded to the other ends of said U-shaped members; and

a reflector spaced from said dipole halves and connected to said connecting member.

2. A directional antenna according to claim 1, wherein said reflector comprises at least two elongate, parallel, spaced-apart members.

3. A directional antenna according to claim 2, wherein said reflector members are U-shaped.

4. A directional antenna according to claim 1, wherein said connecting member includes a weld connecting said U-shaped members to said reflector.

5. A directional antenna according to claim 1, comprising a coaxial cable extending between the legs and base of one of said U-shaped members and connected to said dipole halves.

6. A directional antenna according to claim 5, comprising a mounting sheet connected at adjacent ends of said U-shaped members and wherein said coaxial cable is connected to said one U-shaped member via said mounting sheet.

7. A directional antenna according to claim 6, comprising a second connecting member including insulating material and conductive material, said second connecting member bridging adjacent ends of said U- shaped members adjacent said dipole halves, said coaxial cable terminating at said connecting member.

8. A directional antenna according to claim 5, wherein said coaxial cable includes a first conductor connected to one end of one of said dipole halves and a second conductor connected to one end of the other of said dipole halves, and comprising a conductor bridge included in the last-mentioned connection.

9. A directional antenna accordint to claim 7, comprising transverse plates connecting adjacent ends of said U-shaped members and carrying said connecting member.

3,686,673 6 10. A directional antenna according to claim 9, said U-shaped members. I wherein Said connecting member has a tubular shape 12. A directional antenna according to claim 1, comg s s end plugs closing the connecting prising a plastic housing enclosing adjacent ends of the 11. A directional antenna according to claim 1, 5 ushaped members and the ends of the dipole halves wherein said dipole halves are tubular and each have a connected thereto' a diameter approximately equal to the width of a base of 

1. A directional beam antenna comprising: a pair of parallel spaced-apart U-shaped members each having a pair of legs and a base interconnecting said legs, said legs of each said member extending toward the legs of the other said member; a pair of dipole halves each welded to and extending from respective ones of said bases at one end of said U-shaped members; a connecting member welded to the other ends of said U-shaped members; and a reflector spaced from said dipole halves and connected to said connecting member.
 2. A directional antenna according to claim 1, wherein said reflector comprises at least two elongate, parallel, spaced-apart members.
 3. A directional antenna according to claim 2, wherein said reflector members are U-shaped.
 4. A directional antenna according to claim 1, wherein said connecting member includes a weld connecting said U-shaped members to said reflector.
 5. A directional antenna according to claim 1, comprising a coaxial cable extending between the legs and base of one of said U-shaped members and connected to said dipole halves.
 6. A directional antenna according to claim 5, comprising a mounting sheet connected at adjacent ends of said U-shaped members and wherein said coaxial cable is connected to said one U-shaped member via said mounting sheet.
 7. A directional antenna according to claim 6, comprising a second connecting member including insulating material and conductive material, said second connecting member bridging adjacent ends of said U-shaped members adjacent said dipole halves, said coaxial cable terminating at said connecting member.
 8. A directional antenna according to claim 5, wherein said coaxial cable includes a first conductor connected to one end of one of said dipole halves and a second conductor connected to one end of the other of said dipole halves, and comprising a conductor bridge included in the last-mentioned connection.
 9. A directional antenna accordint to claim 7, comprising transverse plates connecting adjacent ends of said U-shaped members and carrying said connecting member.
 10. A directional antenna according to claim 9, wherein said connecting member has a tubular shape and comprises end plugs closing the connecting member.
 11. A directional antenna according to claim 1, wherein said dipole halves are tubular and each have a diameter approximately equal to the width of a base of said U-shaped members.
 12. A directional antenna according to claim 1, comprising a plastic housing enclosing adjacent ends of the U-shaped members and the ends of the dipole halves connected thereto. 